While electronic temperature control systems using electrical temperature sensing resistors for sensing the space temperature and potentiometers in the electrical circuit for adjusting the temperature setpoint and thus the temperature to be controlled in the space, are very old such as shown in the John M. Wilson et al. U.S. Pat. No. 2,572,293 issued Oct. 23, 1951, there is a continual need for a more compact and less expensive control thermostat apparatus.
The thermostat of this invention provides for an electrical circuit board mounted on a base having a pair of potentiometer wipers associated with the circuit board. The wipers are attached to selector members which are pivotally attached to the base in a compact unit. Specifically, the first selector member carries a wiper and has an opening so that upon the mounting of a second selector member thereupon on the same pivotal support, the wiper of the second selector member can be associated with the circuit board through the opening in the first selector member. While an indicator scale in the base of the thermostat can cooperate with pointers associated with the selector members, the movement of the selector members is an arcuate motion. To provide for selection of the setpoint on the thermostat, adjusting members are mounted on the base for straight line motion and cooperate with the ends of the selector members to provide for the pivotal motion of the selector members.